Biomedical subjects
Calvin M Johnson
Publications and source records attributed to Calvin M Johnson.
Transmission of equine influenza virus to dogs.
Molecular and antigenic analyses of three influenza viruses isolated from outbreaks of severe respiratory disease in racing greyhounds revealed that they are closely related to H3N8 equine influenza virus. Phylogenetic analysis indicated that the canine influenza virus genomes form a monophyletic group, consistent with a single interspecies virus transfer. Molecular changes in the hemagglutinin suggested adaptive evolution in the new host. The etiologic role of this virus in respiratory disease was supported by the temporal association of rising antibody titers with disease and by experimental inoculation studies. The geographic expansion of the infection and its persistence for several years indicate efficient transmission of canine influenza virus among greyhounds. Evidence of infection in pet dogs suggests that this infection may also become enzootic in this population.
Inhibition of simian immunodeficiency virus by foamy virus vectors expressing siRNAs.
Viral vectors available for gene therapy are either inefficient or suffer from safety concerns for human applications. Foamy viruses are non-pathogenic retroviruses that offer several unique opportunities for gene transfer in various cell types from different species. In this report, we describe the use of simian foamy virus type 1 (SFV-1) vector to examine the efficacy of therapeutic genes. Hairpin short-interfering RNA (siRNA) that targets the simian immunodeficiency virus (SIV) rev/env was placed under the control of the PolIII U6 snRNA promoter for expression and screened for silencing target genes using cognate target-reporter fusions. We have identified an effective siRNA (designated R2) which reduces the rev and env gene expression by 89% and 95%, respectively. Using the simian foamy virus type 1 (SFV-1) based vector, we delivered the PolIII expressed R2 siRNA into cultured cells and challenged with SIV. The results show that the R2 siRNA is a potent inhibitor of SIV replication as determined by p27 expression and reverse transcriptase assays. Vectors based on a non-pathogenic SFV-1 vector may provide a safe and efficient alternative to currently available vectors, and the SIV model will help devise protocols for effective anti-HIV gene therapy.
Pulmonary arterial disease in cats seropositive for Dirofilaria immitis but lacking adult heartworms in the heart and lungs.
OBJECTIVE: To determine the prevalence and severity of pulmonary arterial lesions in cats seropositive for heartworms (Dirofilaria immitis) but lacking adult heartworms in the heart and lungs during necropsy. ANIMALS: 630 adult cats from an animal control shelter in Florida. PROCEDURE: Cats were tested for adult heartworms in the heart and pulmonary arteries and antibody against heartworms in the serum. Histologic examination was conducted on the right caudal lung lobe of 24 heartworm- and antibody-positive cats; 24 heartworm-negative and antibody-positive cats; and 24 heartworm-, antibody-, and antigen-negative cats. Wall areas of 10 small to medium-sized pulmonary arteries of each cat were measured and expressed as a proportion of total cross-sectional area. RESULTS: Heartworm infection or seropositive status was significantly and strongly associated with seventy of medial hypertrophy of pulmonary arterial walls. Heartworm- and antibody-positive cats and heartworm-negative and antibody-positive cats had a significant increase in wall thickness, compared with wall thickness for heartworm- and antibody-negative cats. Heartworm- and antibody-positive cats had the most severe hypertrophy. The proportion with occlusive medial hypertrophy was significantly higher in heartworm- and antibody-positive cats (19/24 [79%]) and heartworm-negative and antibody-positive cats (12/24 [50%]), compared with heartworm- and antibody-negative cats (3/24 [13%]). CONCLUSIONS AND CLINICAL RELEVANCE: Cats with serologic evidence of exposure to heartworms, including those without adult heartworms in the lungs and heart, have a greater prevalence of pulmonary arterial lesions than heartworm-negative cats without serologic evidence of exposure. Additional studies are needed to define the pathogenesis, specificity, and clinical importance of these lesions.
Hematopoiesis in the feline fetal liver: an assessment by flow cytometry.
The domestic cat is an excellent model for the development of therapeutic protocols that target hematopoietic stem cells (HSCs) because it is relatively resistant to complications related to bone marrow transplantation. To identify a plentiful source of HSC that could be used as targets for gene transduction and transplantation, the livers of 28 mid-gestation fetuses (28-52 days) and late-gestation fetuses (53 days-term) were analyzed for erythroid, myeloid, lymphoid, and uncommitted hematopoietic progenitor cells by flow cytometry. We found that the fetal liver mononuclear cells (FLMCs) contained 57% erythroid progenitors during mid-gestation, but this percentage declined to 43% as gestation progressed. Myelomonocytic cells within FLMC were more numerous in late-gestation (31%) than in mid-gestation (18%). Two monoclonal antibodies (mAb), CH 152 and CH 755, which recognize cells with the potential to reconstitute multilineage hematopoiesis in cats, were tested. Approximately, 32% of FLMC from late-gestation fetuses expressed the epitope recognized by mAb CH 152, a significant increase above the 12% positive cells in mid-gestation fetuses. Approximately, 33% of hepatic mononuclear cells expressed the epitope recognized by mAb CH 755 in both mid-term and late-term fetuses. When expressed in absolute numbers, medians of 2.7 x 10(7) CH 152-positive cells and 3.2 x 10(7) CH 755-positive cells were extracted from the late-term fetal livers of individual cats. T-lymphocytes were a minor component (<3%) of FLMC, despite their presence in the thymus and spleen. These data suggest that the late-term feline fetal liver is a suitable source of mutipotential hematopoietic cells that could be used for gene therapy protocols in the cat.
Detection and analysis of six lizard adenoviruses by consensus primer PCR provides further evidence of a reptilian origin for the atadenoviruses.
A consensus nested-PCR method was designed for investigation of the DNA polymerase gene of adenoviruses. Gene fragments were amplified and sequenced from six novel adenoviruses from seven lizard species, including four species from which adenoviruses had not previously been reported. Host species included Gila monster, leopard gecko, fat-tail gecko, blue-tongued skink, Tokay gecko, bearded dragon, and mountain chameleon. This is the first sequence information from lizard adenoviruses. Phylogenetic analysis indicated that these viruses belong to the genus Atadenovirus, supporting the reptilian origin of atadenoviruses. This PCR method may be useful for obtaining templates for initial sequencing of novel adenoviruses.
Beta 2 microglobulin and resistance to murine respiratory mycoplasmosis.
Mycoplasma pulmonis (MP) infection causes murine respiratory mycoplasmosis (MRM) in mice. This study was designed to determine whether C57BL/6 beta 2 microglobulin knockout (KO) mice (B2m-/-) differed from C57BL/6 B2m(+/+) wild-type (WT) mice in the early events of acute infection and to confirm previous studies that suggested loss of beta 2 microglobulin (B2m) expression was correlated with increased disease susceptibility. Experimentally infected mice were necropsied at various time points after infection. Quantitative cultures were performed on lung, trachea, and nares at each time point. Tissues were collected for histopathology. Both genotypes had marked clearance of MP from all sites within the first 24 h post-infection (p.i.). There were no differences between KO and WT mice in the ability to clear MP from the lung, nares, or trachea during the first 48 h p.i. During chronic infection, there was a significant difference among days p.i. for number of MP isolated from the lungs, nares, and trachea (P<0.05). There were significant differences (P<0.05) between genotypes for number of MP isolated from the lung. Numbers of MP isolated from KO mice were greater than from WT mice at day 10 through day 28 p.i. There was no significant overall difference between genotypes for number of MP isolated from the nares or trachea. However, increased numbers of MP were isolated from the nares of KO mice at days 21 and 28 p.i. and from the trachea of KO mice at days 7 and 21 p.i. During chronic infection, KO mice had increased facial scratching and altered respiration as well as marked weight loss compared with those of WT mice. The KO and WT mice differed (KO more severe) with respect to the presence and extent of neutrophilic exudate in the lung. Differences approached significance for consolidation of lung parenchyma but not for lymphoid infiltration, tending to be more severe in KO mice. Loss of B2m does not appear to affect clearance of MP during the critical first 48 h of infection but does seem to affect chronic infection, which may be because of the loss of CD8(+) Tc1 cells, the CD1-B2m complex, or both.
The deep plane facelift.
The goal of any cosmetic facial plastic surgery procedure is to obtain a natural-appearing result that is not overdone or obviously operated upon. This is the case whether the background of the operating surgeon is in facial plastic and reconstructive surgery, general plastic surgery, dermatology, or oculoplastic surgery. To satisfy this goal, the surgeon must apply those techniques that consistently achieve effective but understated results rather than experimenting with every new innovation or fad. More and more surgeons are moving away from some of the so-called advances of the last decade, including the use of lasers for skin resurfacing and the application of endoscopic approaches to the face, in the search for the best results possible. Sometimes this means utilizing older techniques that have proven the test of time, such as the coronal browlift and chemical peels, whereas other times this means embracing those newer techniques that clearly represent major advances in our specialty, such as the transconjunctival approach to lower lid blepharoplasty. The deep plane facelift is one such advance. In contrast to traditional, skin or short-SMAS flap techniques, the deep plane facelift allows the surgeon to consistently obtain a natural-appearing result that not only addresses the key areas of concern in the aging face but also proves to be longer lasting as well. The deep plane technique also results in fewer complications, an improved ability to address the melolabial region and jowls, and increased anatomic appeal for the operating surgeon.
Immunodeficiency associated with multiple concurrent infections in captive Pallas' cats (Otocolobus manul).
Five neonatal Pallas' cats (Otocolobus manul) at the Oklahoma City Zoo died from toxoplasmosis with concurrent herpesvirus infection. These multiple infections suggested underlying immunodeficiency, perhaps caused by concurrent infection with feline immunodeficiency virus (FIV); so blood samples were collected for serology, serum protein electrophoresis, lymphocyte proliferation assays, and cytokine analysis by reverse transcriptase-quantitative competitive polymerase chain reaction (RT-qcPCR). Resulting data were compared with data from FIV-infected and control domestic short-haired cats. In addition, peripheral blood mononuclear cell cultures were propagated to detect FIV virus by both RT-qcPCR and detection of reverse transcriptase activity. Serum protein electrophoresis showed that four of six Pallas' cats had increased alpha, globulins. At least two Pallas' cats had decreased lymphoproliferation responses to mitogen. and all three tested animals exhibited defective interleukin-12 gene expression. Although these clinical and laboratory findings suggested an immunodeficiency syndrome, FIV infection could not be confirmed. On the basis of repeated blood test results, it can be concluded that nutritional, metabolic, or other systemic problems probably did not contribute to the disease syndrome. Further investigation of other possible causes of immunodeficiency, including a possible genetic component, in this population is needed.
Transduction of umbilical cord blood CD34+ NOD/SCID-repopulating cells by simian foamy virus type 1 (SFV-1) vector.
Foamy viruses are nonpathogenic retroviruses that offer unique opportunities for gene transfer into various cell types including hematopoietic stem cells. We used a simian foamy virus type 1 vector (SFV-1) containing a LacZ reporter gene with a titer of 1-5 x 10(6) viral particles/ml that was free of replication-competent retrovirus to transduce human umbilical cord blood CD34+ cells. Transduced CD34+ cord blood cells were transplanted into NOD/SCID mice and plated in serum-free methylcellulose culture to determine the transduction efficiency of human hematopoietic progenitor cells. A transduction efficiency of about 20% was obtained. At 6-10 weeks posttransplantation, human hematopoietic cell engraftment and marking were determined. Marrow from transplanted mice demonstrated human cell engraftment by the presence of human (CD45+) cells containing both CD19+ lymphoid and CD33+ myeloid cells. Serial sampling of NOD/SCID bone marrow revealed the presence of 6.7-14.0% CD45+ cells at 6 weeks posttransplant as compared to 3.6-27.2% CD45+ cells at 9-10 weeks posttransplant. Human progenitors examined from NOD/SCID bone marrow cells 9 weeks posttransplant revealed from 7.4 to 25.9% of the colonies exhibiting X-gal staining. Our study demonstrates the ability of a simian foamy virus vector to transduce the SCID-repopulating cell and offers a promising new gene delivery system for use in hematopoietic stem cell gene therapy.
Skin and subcutaneous tissue in rhinoplasty.
Explore the source record for details and available documents.
Cosmetic surgery procedures as luxury goods: measuring price and demand in facial plastic surgery.
OBJECTIVES: To evaluate the relationship between cosmetic facial plastic surgery procedure price and demand, and to test the hypothesis that these procedures function as luxury goods in the marketplace, with an upward-sloping demand curve. METHODS: Data were derived from a survey that was sent to every (N = 1727) active fellow, member, or associate of the American Academy of Facial Plastic and Reconstructive Surgery, assessing the costs and frequency of 4 common cosmetic facial plastic surgery procedures (face-lift, brow-lift, blepharoplasty, and rhinoplasty) for 1999 and 1989. An economic analysis was performed to assess the relationship of price and demand for these procedures. RESULTS: A significant association was found between increasing surgeons' fees and total charges for cosmetic facial plastic surgery procedures and increasing demand for these procedures, as measured by their annual frequency (P</=.003). After a multiple regression analysis correcting for confounding variables, this association of increased price with increased demand holds for each of the 4 procedures studied, across all US regions, and for both periods surveyed. CONCLUSIONS: Cosmetic facial plastic surgery procedures do appear to function as luxury goods in the marketplace, with an upward-sloping demand curve. This stands in contrast to other, traditional, goods for which demand typically declines as price increases. It appears that economic methods can be used to evaluate cosmetic procedure trends; however, these methods must be founded on the appropriate economic theory.
The evolution of open structure rhinoplasty.
Modifications and innovations in open structure rhinoplasty that have occurred as this technique has evolved are discussed. In addition, the philosophy and fundamentals of open structure rhinoplasty are reexamined. A retrospective review of representative patients in a private practice setting was performed. All surgical procedures were conducted in a freestanding private surgery center. The preoperative and long-term results of each patient are compared to demonstrate the effectiveness of the described techniques. The fundamental philosophy of open structure rhinoplasty is the maintenance of the integrity and strength of the nasal skeleton. Modifications of tip grafting techniques, along with additional domal grafting techniques, and a stronger focus on domal suturing techniques result in a softer contour and lack of tip tensions while maintaining structural support.
In vitro development and characterization of a manatee bronchial cell line.
In the present study, culture conditions that promote the growth and differentiation of manatee respiratory tract epithelial cells toward a mucociliary phenotype were determined. Characterization of a manatee-specific cell line enables investigators to conduct in vitro testing where live-animal experimentation is not possible. Cell cultures were established from both explants and enzymatically dissociated cells that were isolated from manatee bronchial tissue. To modulate their differentiation, bronchial epithelial cells were grown on Transwell collagen membranes either submerged or at an air-liquid interface. Growth on a collagen membrane at an air-liquid interface and medium supplemented with retinoic acid was required to promote a mucociliary phenotype. When cells were grown in submerged cultures without retinoic acid, they appeared more squamous and were not ciliated. Intracellular keratin proteins were detected in both submerged and interface cultures. Cultured manatee bronchial epithelial cells will facilitate future studies to investigate their potential role in pulmonary disease associated with brevetoxicosis after exposure to the red-tide organism, Karenia brevis.